Unported head quickness?
I went 13.4 @ 106mph last weekend with no traction whatsover with atrocious 2.35 and worse 60ft times and lost puff at top end with fuel starvation. The M/T ET Radials 255/60/15 didn't want to stick at all and this was in 95 degree heat and fuel was boiling up pretty bad and was spluttering everywhere. With new 275/60/15's to put on and good weather I should easily get in the 12's (hopefully)..